Cyclooctadecanonaene

Cyclooctadecanonaene
Structural formula of cyclooctadecanonaene
Ball-and-stick model of the cyclooctadecanonaene molecule
Identifiers
3D model (Jmol) Interactive image
ChemSpider 120988 N
PubChem 137294
Properties
C18H18
Molar mass 234.34 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Cyclooctadecanonaene or [18]annulene is an annulene with chemical formula C
18
H
18
. This hydrocarbon obeys Hückel's rule and is, therefore, an aromatic compound. Theoretical studies show that [18]annulene has only three completely delocalized π bonds associated with its aromaticity, while other six π bonds represent the conjugated 3c-2e π bonds on the periphery of [18]annulene.[1] The compound was first synthesised by Franz Sondheimer.[2]

Reactions

The original synthesis started by the Eglinton reaction of the di-alkyne 1,5-hexadiyne with copper(II) acetate in pyridine to give the trimer, followed by deprotonation and isomerization with potassium tert-butoxide in tert-butanol and was concluded with hydrogen organic reduction with the Lindlar catalyst.[3] [4]

See also

References

  1. Ivanov, A.; Boldyrev. A (2014). "Deciphering aromaticity in porphyrinoids via adaptive natural density partitioning". Org. Biomol. Chem. doi:10.1039/C4OB01018C.
  2. In the literature and some internet references, Sondheimer is sometimes misspelled as Sandheimer.
  3. Sondheimer, F., Wolovsky, R. and Amiel, Y. (1962). "Unsaturated Macrocyclic Compounds. XXIII. The Synthesis of the Fully Conjugated Macrocyclic Polyenes Cyclooctadecanonaene ([18]Annulene), Cyclotetracosadodecaene ([24]Annulene), and Cyclotriacontapentadecaene ([30]Annulene).". J. Am. Chem. Soc. 68 (2): 274–284. doi:10.1021/ja00861a030.
  4. K. Stöckel and F. Sondheimer (1988). "[18]Annulene". Org. Synth.; Coll. Vol., 6, p. 68
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